This invention relates to insert fittings for convoluted tubing and/or hose. More particularly, the invention relates to fluid sealing efficiencies of hose-to-fitting coupling mechanisms.
The majority of prior art fitting inserts for convoluted hose and tubing have either entirely smooth, fully cylindrical surfaces or have barbed projections emanating from smooth cylindrical surfaces. In some instances, grooved inserts are utilized which have annular ridges believed to enhance the crimping process, and hence efficiency, of the fluid seal between the tubing and nipple insert portions of the fitting. Generally, regardless of which type of nipple insert is utilized, the convoluted tubing end is compressed against the insert during the crimping process, and the individual convolutions tend to collapse in random folding patterns, making relatively difficult the task of establishing a reliable fluid seal. In fact, in most applications, potential leaks and variations associated with randomly compressed convoluted tubing become even more difficult to predict and control when the fittings are barbed or have annular grooves over their cylindrical surfaces.
Ideally, a fitting insert would be designed such that the collapse of convoluted tubing during the crimping step could be controlled in a manner to assure and even to enhance fluid sealability.